666221878514 has 8 divisors (see below), whose sum is σ = 1016270662320. Its totient is φ = 327464991076.

The previous prime is 666221878507. The next prime is 666221878549. The reversal of 666221878514 is 415878122666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 666221878514.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2822973944 + ... + 2822974179.

It is an arithmetic number, because the mean of its divisors is an integer number (127033832790).

Almost surely, 2^666221878514 is an apocalyptic number.

666221878514 is a deficient number, since it is larger than the sum of its proper divisors (350048783806).

666221878514 is a wasteful number, since it uses less digits than its factorization.

666221878514 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5645948184.

The product of its digits is 7741440, while the sum is 56.

The spelling of 666221878514 in words is "six hundred sixty-six billion, two hundred twenty-one million, eight hundred seventy-eight thousand, five hundred fourteen".